Page 341 - Subyek Teknik Mesin - Forsthoffers Best Practice Handbook for Rotating Machinery by William E Forsthoffer

Be st Practice 5 .17 Steam Turbine Best Practices

Best
Best
Best Practice 5.17Practice 5.17Practice 5.17
Check the freedom of movement of a single valve, steam Lessons Learned
turbine, governor system every three months, by slowly Failure to exercise single valve steam turbines has led to
closing the turbine inlet block valve and observing gover- critical compressor train trips because:
nor valve stem movement. Note: First confirm that the A tachometer was not installed
governor valve is not fully open. Friction bound governor linkages have resulted in undetected
Single stage steam turbine linkages can easily become friction speed reductions during steam header upsets
bound. The motor driven auxiliary pump did not start in time to prevent
Check their freedom of movement every three months and free up a low lube oil pressure trip
linkages and coat all bushings with Moly Cote (high temperature
grease), or equivalent if required.
Linkages commonly become friction bound after a turnaround or Benchmarks
extended shutdown, since any steam deposits can set up and harden This best practice has been recommended since 1985, when multiple
in the valve stem packing area. friction-bound linkage issues were experienced during the start-up of
a chemical plant in the Middle East.

B.P. 5.17. Supporting Material

Please refer to material in B.P. 5.14.

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